1. Field of the Invention
The present invention relates to a light emitting diode (LED) package and a backlight using the same, and more particularly, to an LED package which includes a lens whose upper side for refracting the light from an LED has a convex surface with a large angle of beam, by which the shape of the lens and an assembly process can be simplified, and a backlight unit using the same.
2. Description of the Related Art
Recently, there exists a need for a large-sized Liquid Crystal Display (LCD) capable of outputting a large-sized image. In the case of using a Cold Cathode Fluorescent Lamp (CCFL) for a light source of the LCD, there are spatial and environmental limitations with use of mercury. Thus, a Light Emitting Diode (LED) with its high efficiency and advantage for miniaturization is widely used for the light source of the LCD.
With the current trend of compact products, the LCDs are also miniaturized these days. Recently, there have been suggested an LED package, which is configured to have a larger beam angle of an LED, thereby achieving miniaturization, and a backlight unit using the same.
Now, a conventional LED package and a backlight unit using the same will be explained in detail with reference to the accompanying drawings.
FIG. 1 is a sectional view illustrating the conventional LED package, and FIG. 2 is a sectional view illustrating the backlight unit using the conventional LED package.
The conventional LED package shown in FIG. 1 includes a housing 10, a lens 20 seated in the housing 10 and an LED provided inside the lens 20.
The lens 20 has a funnel-shaped recess on an upper surface thereof, with its outer surface narrowing downward, thereby laterally emitting the light from the LED 30. Here, the outer surface of the lens 20 may be shaped not only as illustrated in FIG. 1 but also in complex and various forms as suggested in U.S. Pat. No. 6,598,998. In addition, such LED packages 1 emitting three different colors are mounted in the backlight unit to suitably mix the colors, thereby outputting a desired color of light.
As shown in FIG. 2, the light laterally emitted through a side surface of the LED 30 is reflected by a reflecting member 2 having a curved surface and thereby refracted upward. This results in a greater beam angle of light emitted from the LED 30 and allows the backlight unit to be manufactured with a fewer number of LED packages 1.
However, in the backlight unit with the above configuration, the LED package 1 refracts light laterally using the difference in the refractive indices of the lens 20 and thus cannot completely block the light beams emitted upward through a central portion. Therefore, bright spots are exhibited in the portions corresponding to the positions of the LED packages 1. To eliminate such bright spots, a separate sheet is required, increasing the manufacturing costs.
Moreover, the complex shape of the lens 20 requires a difficult manufacturing process and entails limitations in the lens material. Further, in the case of using the above described lens 20, a large-sized LED 30 of at least 1 mm2 is suitable, which however results in low light efficiency.